Printing Apparatus and Methods

ABSTRACT

Printing apparatus comprise a printing table, a loader to load sheets of print media to the printing table, and a moveable tray on which at least one row of media sheets can be placed, the tray being moveable between a position in which it is accessible to an operator for placing media sheets thereon and another position in which at least part of the tray is accessible to the loader for picking the print media sheets but inaccessible to the operator.

RELATED DOCUMENTS

The present application is a continuation of U.S. application Ser. No.14/320,178 filed Jun. 30, 2014, which claims the benefit under 35 U.S.C.§119(b) of European Patent Application No. 13178656.1, filed Jul. 30,2013. These applications are herein incorporated by reference in theirentireties.

BACKGROUND

Large format flatbed printers may be employed to print signs, banners,posters or the like, on rigid or flexible sheets of media of severalmaterials, sizes and thicknesses. The sheets may be printed whilesupported on a printing table: suitable loaders, for example havingvacuum cups, may be provided to pick up media sheets from a loading topor surface, transfer them to the printing table, and remove them fromthe printing table after printing.

The loading top may generally be arranged on one side of the printer. Anoperator, or an automatic pre-set loading machinery, may place on theloading top a large media sheet to be printed, or a row of severalsmaller media sheets, parallel to each other and aligned in a directionat right angles with respect to the movement of the loader. The loadermay then pick up and transfer to the printing table the large sheet,using several vacuum cups; in the case of a row of sheets, it can pickup the sheets of the row using one or more cups for each sheet, andtransfer several sheets at the same time to the printing table.

For security reasons, a cover may enclose the loader, leaving only a lowelongate opening in correspondence with the loading top, allowing thepassage of the sheets of media. The operator may thus place a sheet onthe loading top, pushing the sheet such that its leading edge slipsunder the cover through the opening and reaches a position where part ofthe sheet is accessible and may be picked up by the loader. The operatoris therefore isolated from the loader at all times.

BRIEF DESCRIPTION OF THE DRAWINGS

Some non-limiting examples of devices which may be employed to monitor amedia roll mounted in a printing apparatus will be described in thefollowing with reference to the appended drawings, in which:

The accompanying drawings illustrate various examples of the principlesdescribed herein and are a part of the specification. The illustratedexamples are given merely for illustration, and do not limit the scopeof the claims.

FIG. 1 schematically shows in elevation view an example of a printingapparatus as provided herein;

FIG. 2 schematically shows in elevation view another example of aprinting apparatus as provided herein, in different operationalsituations, illustrating an example of a printing method;

FIG. 3 schematically shows a further example of a printing apparatus indifferent operational situations, in this case in plan view;

FIGS. 4 and 5 schematically shows in perspective view examples ofmoveable trays of printing apparatus as described herein,

FIG. 6 schematically shows an example of a printing apparatus asdescribed herein with a tiltable tray; and

FIG. 7 schematically shows an example of a tray with a tiltingarrangement and a driving arrangement.

DETAILED DESCRIPTION

In flatbed printers such as mentioned above, in which an operator placesprint media sheets on a stationary loading top, sheets can only beintroduced under the cover of the loader up to a certain depth, becausethe operator must hold them and push them, slipping the leading edgeunder the cover. Consequently, only one row of sheets may be madeaccessible to the loader, the loader can only pick the sheets in oneposition, and only one row of sheets can therefore be loaded on theprinting table for a printing operation.

According to some examples, printing apparatus, such as a large formatflatbed digital printer, as provided herein comprise a printing tableand a loader to load sheets of print media to the printing table, andfurther comprise a moveable tray on which at least one row of mediasheets can be placed; this tray is moveable between a position in whichit is accessible to an operator for placing media sheets thereon andanother position in which at least part of the tray is accessible to theloader for picking the print media sheets, but is inaccessible to theoperator.

A tray moveable between these two positions allows improving throughputof the apparatus without affecting the operator's security, because thetray may be safely positioned under the cover at several depths,including a depth that is larger than the sheet dimension in thedirection of the depth: it is not necessary to leave part of the sheetoutside the cover. Sheets can therefore be made accessible to the loaderat least at two depth positions, such that more than one row of sheetsmay be picked and placed on the printing table for a printing operation;and this without the need for the operator to reach the area ofinfluence of the loader.

FIG. 1 is an elevation view of an example of a printing apparatus, whichmay be a large format flatbed printer, with a printing table 10 and aloader 20 to load sheets of print media to the printing table 10.

The loader may be provided with suction cups, for example two sets ofcups 21 a-21 b and 22 a-22 b, each with two rows of cups as shown in thefigure to pick up, transport and release two rows of sheets of printmedia. The loader 20 may be enclosed at least partly by a safety cover30, to prevent an operator from being injured by interfering with themovement of the loader.

The loader 20 may move horizontally, as shown by arrow A, and thesuction cups may be raised and lowered as shown by arrow B in order toapproach in each case the surface from which the sheets have to bepicked or the surface on which they have to be placed.

The apparatus may further comprise a moveable tray 40, on which at leastone row of media sheets (not shown in FIG. 1) can be placed.

In the present specification a “row” of sheets, or a “row” of suctioncups, is intended to designate a number of sheets or cups that arealigned in a direction which is horizontal and at right angles to thehorizontal movement of the loader, i.e. the direction of arrow A ofFIG. 1. A row of sheets may include two or more sheets, but also asingle sheet.

The tray 40 may be moveable, for example as shown by arrow C, between aposition (in solid lines in FIG. 1) in which it is accessible to anoperator for placing media sheets thereon, and another position (indashed lines in FIG. 1) in which at least part of the tray 40 isaccessible to the loader 20 for picking the print media sheets, butinaccessible to an operator that is manually laying sheets of printmedia on the tray 40.

With the layout of FIG. 1, an operator may be positioned at the lefthand side of the figure.

The tray 40 may be made inaccessible to the operator either by a safetycover enclosing at least partly the loader, such as cover 30 in FIG. 1,or by implementing other safety provisions to prevent the operator fromreaching the part of the tray that is under the influence of the loader(for example the position in dashed lines in FIG. 1).

However, in some examples, part of the tray may remain accessible to theoperator also in the position in which another part of the tray isaccessible to the loader: for example, the side of the tray that isremote from the loader and the printing table may remain accessible tothe operator in order to be pulled back once the loader has emptied it.

The cover 30 may leave a low elongate opening 31 in order to allow thepassage of the tray 40 under the cover, towards the position where it isaccessible to the loader 20.

As shown in FIG. 1 a printing apparatus as disclosed may also comprise areception table or lift 50, on which the loader may place the printedsheets after they have been printed.

In some examples the tray 40 may be slidable horizontally between thetwo positions: for example, it may be slidable over a structure 60(FIG. 1) with a smooth upper surface, guides, or other supportingarrangements.

A printing method as disclosed herein may comprise, according to someexamples:

-   placing at least one row of media sheets on a moveable tray, such as    tray 40 shown in FIG. 1;-   moving said tray to a position, such as the position shown in dashed    lines in FIG. 1, where at least part of the tray is accessible to a    loader 20 and inaccessible to an operator; and-   causing the loader 20 to pick media sheets from the tray 40 and load    them to a printing table 10 in a printing apparatus.

In some examples, the tray 40 may be moved to the position where atleast part of it is accessible to the loader 20 by sliding ithorizontally.

An example of a printing method will be described in more detail in thefollowing with reference to FIG. 2, which schematically shows an exampleof a printing apparatus in several operating situations A, B, C, D andE.

In the apparatus of this figure the loader 20 comprises two rows ofsuction cups 21 a-21 b and 22 a-22 b, each row corresponding with a rowof media sheets that may be placed on the moveable tray 40 to betransferred to the printing table.

In situation A, two rows of media sheets S1 and S2 are on the printingtable 10, and the tray 40 is in a position accessible to an operator (atthe left hand side of the figure), who may place two new rows of printsheets S3 and S4 on its surface.

The tray 40 may then be slid (arrow A1) to a position partly under thecover 30, as shown in the second drawing of FIG. 2 (situation B), wherethe rows of sheets S3 and S4 are respectively accessible to the rows ofsuction cups 21 a and 21 b of loader 20, while this part of the trayunder the influence of the loader 20 is inaccessible to the operator byvirtue of cover 30. At the same time, the rows of cups 22 a and 22 b ofthe loader are positioned over the rows of printed sheets S1 and S2,respectively.

In situation B, however, part of the tray 40, and part of each sheet ofthe row of sheets S4, may remain outside the cover 30 and be accessibleto the operator, since sheets may be picked up by the cups near theirleading edge in the direction of movement, as shown in the figure.

In this situation, the loader 20 is lowered as shown by arrow B1, andall the suction cups are activated to pick up the sheets.

In situation C, the loader 20 raises the four rows of sheets S1, S2, S3and S4 that have been engaged by respective suction cups, and moves themtowards the right in the figure, as shown by arrow C1; as a result, rowsof sheets S1 and S2 are transferred towards the reception table 50,while rows of sheets S3 and S4 are transferred towards the printingtable 10.

In situation D, the loader 20 descends as shown by arrow D1, and thesuction cups release the sheets, such that rows of sheets S1 and S2 arelaid on the reception table or lift 50, while rows of sheets S3 and S4are laid on the printing table 10. At the same time, the tray 40 iswithdrawn out of the cover 30, as shown by arrow D2, towards theposition in which all or almost all the tray is accessible to theoperator.

In situation E the loader has gone back to the initial position, asshown by arrow E1, and the apparatus is again in the operating situationwherein two rows of media sheets (now S3 and S4) are being printed onthe printing table, and the tray 40 is being filled with two new rows ofprint sheets S5 and S6 by an operator.

In examples of printing methods as described in relation to FIG. 2, theapparatus throughput may be increased, while at the same timemaintaining satisfactory security conditions: indeed, the operator canload multiple rows at different depths inside the cover 30, such thatmultiple rows of sheets may be printed simultaneously in the apparatus,and this is done without reaching with hands or other parts of the bodythe area where the loader is working.

The tray 40 may be moved between the two positions manually by theoperator, or by means of a driving arrangement, as will be describedlater.

Other examples of printing apparatus and printing methods as providedherein are now described with reference to FIG. 3.

FIG. 3 is a very schematic plan view of an example of a printingapparatus as provided herein, in several operating situations A, B, C,D, E and F. The figure shows a tray 40′, a set of suction cups with tworows 21 a and 21 b belonging to a loader that is otherwise not shown,and a stationary safety cover 30 that encloses at least part of theloader. An operator (not shown) may stand near the edge of the tray 40′that is remote from the cover 30.

The cover 30 is stationary throughout the operation described in thefollowing. In the figure, the end of the cover 30 has been referencedusing a dot-and-dash line extending between the drawings that show thedifferent situations A to F.

In situation A, an operator places a first row of four media sheets S1on the tray 40′. The tray is then moved under the cover 30 in thedirection of arrow A1, until it reaches the depth of the first row ofsuction cups 21 a.

In situation B, the first row of sheets S1 is under the cups 21 a andmost of the tray is under cover 30, inaccessible to the operator exceptfor its trailing part. The loader is lowered, the cups 21 a engage thesheets S1 (hatching of the cups in the figure is meant to indicate thatvacuum is applied), and the loader is raised again.

Then, in situation C1, the empty tray 40′ is withdrawn towards theoperator's position as shown by arrow C1.

Next, in situation D, the operator places a second row of media sheetsS2 on the tray 40′, and the tray is moved under the cover 30 in thedirection of arrow D1, until it reaches the depth of the second row ofsuction cups 21 b, i.e. a smaller depth than in situation B.

In this case a larger part of the tray 40′ remains outside the cover 30with respect to situation B, but there is a part of the tray 40′, withthe leading edge of the sheets S2, that is under the cover andinaccessible to the operator.

In situation E, the loader is again lowered, the cups 21 b engage thesheets S2, and the loader is raised again, now bearing the two rows ofsheets S1 and S2.

The empty tray 40′ is again withdrawn towards the operator's position insituation F, as shown by arrow F1. At the same time, the loader bearingthe sheets S1 and S2 moves in the direction shown by arrow F2, totransfer the sheets to a printing table (not shown).

Two rows of print media sheets S1 and S2 may therefore be loaded on theprinting table, and printed simultaneously, thus improving thethroughput of the process.

Also disclosed herein are moveable trays for feeding print media toprinting apparatus, for example large format flatbed printers, such astrays 40 or 40′ described above. Such trays comprise a media supportsurface which is provided with an array of sheet holders. The sheetholders allow positioning print media sheets at predetermined positionson the surface, and also restrict the movement of the sheets in at leastone direction on the media support surface.

In some examples, the sheet holders may restrict the movement of thesheets in a direction opposite to the direction in which, in use, thetray is intended to travel between a position in which it is accessibleto an operator for placing media sheets on the media support surface,and another position in which at least part of the tray is inaccessibleto the operator and accessible to a loader for picking the print mediasheets and transfer them to a printing table of a printing apparatus.

The sheet holders facilitate accurate positioning of the sheetsthroughout the feeding process, such that the sheets may be accuratelypositioned on the printing table.

FIGS. 4 and 5 show examples of moveable trays with sheet holders.

In FIG. 4 a tray 40 may comprise an array of sheet holders 41 on a mediasupport surface 42, to position (in the shown example) up to eight printmedia sheets at predetermined positions on surface 42.

The sheet holders 41 may be configured for example as recesses orpockets, as shown in the figure, into which the sheets may be positionedso that they will be restrained from moving over the surface 42 when thetray travels during use in a printing apparatus as explained for examplein relation to FIGS. 1 to 3 above.

Movable trays such as disclosed herein may be integrated or attached toa printing apparatus, or may be stand-alone devices intended to be usedin combination with a printing apparatus. An operator may for exampleplace a stand-alone tray on a loading top of the printing apparatus,place sheets on the tray, and slide the tray over the loading top to aposition where at least part of the tray is accessible to the loader ofthe apparatus and is inaccessible to the operator.

The number of rows and the number of sheet holders in each row of thearray may vary, depending on the printing apparatus, the size and numberof sheets to be printed, etc. For example, FIG. 5 shows a similarexample of a tray 40′, which has only one row of pockets 41 and may beemployed for example as described in relation to FIG. 3 above.

Other configurations of sheet holders are possible. In some examples,sheet holders may comprise vacuum suction elements (not shown): vacuummay be employed in combination with recesses in the surface, for exampleapplying vacuum via a number of through holes in the bottom of eachrecess, but also in other different configurations of the sheetsholders, or as the sheet holder system itself.

In examples of printing apparatus as provided herein, at least part ofthe tray may be tiltable around a horizontal tilting axis 43 when it isin the position in which it is accessible to an operator. A printingmethod may comprise placing the media sheets on the tray while the trayis tilted at an angle with respect to a horizontal plane, and thenlaying the tray horizontal before moving it to said position where thesheets are accessible to a loader.

FIG. 6 shows schematically part of a printing apparatus in two phases ofan example of a printing method in which the tray may be tilted at anangle. The figure shows a structure 60 on which a tray 40 may besupported and may slide. The structure 60 may have an inclined portion61 at the end where the operator may stand to place sheets on the tray40.

As visible in the first phase of FIG. 6, the operator may rest the tray40 on the inclined portion 61 of the structure, which may have a stop orabutment to hold the tray 40. In this position, the upper part of thetray 40 is brought closer to the operator, facilitating the placement ofsheets in this part of the tray.

After the sheets have been placed of the tray, the operator may tilt thetray 40 back to a horizontal position, as shown in the second phase ofthe figure, and push it as shown by the arrow towards the positionaccessible to the loader 20.

Examples of printing apparatus as provided herein may comprise a drivingarrangement for tilting the tray and/or for displacing the tray betweenits two positions. FIG. 7 shows a schematic example of a tray 40″ whichmay be tilted and moved between its two positions by a drivingarrangement.

As shown in the figure, a pneumatic cylinder 80 may be provided, forexample attached to a supporting structure (not shown). The assembly maybe associated with a printing apparatus, or may be a stand-alone deviceto be arranged on the side of such an apparatus.

A tray 40″ may be attached to the piston rod of cylinder 80, in such away to be rotatable or tiltable around a hinge point 43 that moves withthe piston rod.

A second pneumatic cylinder 70 may be also mounted such as to move withthe piston rod of cylinder 80. The free end of the piston rod ofcylinder 70 may be hinged to an intermediate point 44 under the tray40″, such that the operation of the cylinder 70 may cause rotation ofthe tray 40″ between the horizontal position shown in the figure and atilted position in which the tray is inclined towards the position ofthe operator (at the left hand side of the figure).

When the tray 40″ is horizontal, the cylinder 80 may bring it from theposition of FIG. 7 (accessible to an operator) to a position towards theright, where it may be at least partly accessible to a loader andinaccessible to the operator as indicated by arrow C. In this manner,the tray 40 may be moveable, for example as shown by arrow C, between aposition (in solid lines in FIG. 1) in which it is accessible to anoperator for placing media sheets thereon, and another position (indashed lines in FIG. 1) in which at least part of the tray 40 isaccessible to the loader 20 for picking the print media sheets, butinaccessible to an operator that is manually laying sheets of printmedia on the tray 40 as depicted in FIG. 1.

Even though a single cylinder 80 and a single cylinder 70 have beenshown in the figure, the structure of such a tray 40″ may employ forexample two parallel and spaced apart cylinders 80 and two parallel andspaced apart cylinders 70, and frame components as needed to mount thetray and cylinders 70 on the piston rods of cylinders 80.

In examples of a printing apparatus having for example a drivingarrangement for moving the tray between the two positions, a sensor 90may be foreseen to detect the presence of a media sheet on the tray.Such a sensor 90 may be arranged in correspondence with a position onthe tray which is intended to receive a media sheet, and cause themovement of the tray when it detects the presence of a sheet. Such asensor 90 may be placed in a position on the tray intended to be thelast place where the operator lays a print media sheet.

In examples of the printing methods and apparatus disclosed herein, theoperator may be a human operator, but any automatic pre-set loadingmachinery may also be employed to place the sheets on the movable tray.

Although only a number of particular embodiments and examples have beendisclosed herein, further variants and modifications of the disclosedapparatus and methods are possible; other combinations of the featuresof embodiments or examples described are also possible.

What is claimed is:
 1. A printing apparatus comprising: a printingtable; a loader to load sheets of print media to the printing table; amoveable tray on which at least one row of media sheets are placed, saidmoveable tray being moveable between a position in which it isaccessible to an operator for placing media sheets thereon and anotherposition in which at least part of the moveable tray is accessible tothe loader for picking the print media sheets but inaccessible to theoperator; and a safety cover enclosing the loader, wherein at least aportion of the moveable tray and a portion of the at least one row ofmedia sheets remain outside the cover and accessible to the operatorwhen the movable tray is in the another position in which at least partof the moveable tray is accessible to the loader.
 2. The printingapparatus of claim 1, wherein the moveable tray comprises a mediasupport surface provided with sheet holders to position print mediasheets at predetermined positions on the surface and restrict movementof the sheets in at least one direction on the media support surface. 3.The printing apparatus of claim 2, wherein the media support surface isprovided with an array of sheet holders to position at least two rows ofprint media sheets.
 4. The printing apparatus of claim 2, wherein eachsheet holder comprises a recess in the media support surface.
 5. Theprinting apparatus of claim 2, wherein the loader comprises vacuumsuction elements.
 6. The printing apparatus of claim 1, wherein thecover makes part of the moveable tray inaccessible to the operator whenthe moveable tray is in the position accessible to the loader.
 7. Theprinting apparatus of claim 1, wherein the moveable tray is slidablehorizontally between said two positions.
 8. The printing apparatus ofclaim 1, wherein at least part of the moveable tray is tiltable around ahorizontal tilting axis when it is in the position in which it isaccessible to an operator.
 9. The printing apparatus of claim 1, furthercomprising a driving arrangement for displacing the moveable traybetween the two positions.
 10. The printing apparatus of claim 9,further comprising a sensor to detect the presence of a media sheet onthe moveable tray, arranged in correspondence with a position on themoveable tray which is intended to receive a media sheet, wherein, inresponse to a detection of the media sheet on the moveable tray by thesensor, moving the tray in the another position in which at least partof the moveable tray is accessible to the loader for picking the printmedia sheets.
 11. The printing apparatus of claim 3, wherein the loadercomprises at least two rows of suction cups, each row corresponding witha row of media sheets placed on the moveable tray.
 12. A printing methodcomprising: placing at least one row of media sheets on a moveable tray;with a number of sensors to detect the presence of a media sheet on themoveable tray, in response to a detection of the media sheet on themoveable tray by the sensors, moving said moveable tray to a positionwhere at least part of the moveable tray is accessible to a loader andinaccessible to an operator; and causing the loader to pick media sheetsfrom the moveable tray and load them to a printing table in a printingapparatus.
 13. The method of claim 12, wherein the moveable tray ismoved to said position where at least part of it is accessible to aloader by sliding it horizontally.
 14. The method of claim 12, furthercomprising placing the media sheets on the moveable tray while themoveable tray is tilted at an angle with respect to a horizontal plane,and laying the moveable tray horizontal before moving it to saidposition where the sheets are accessible to a loader.
 15. The method ofclaim 12, further comprising defining a number of recesses in a mediasupport surface of the moveable tray, the recesses forming an array ofsheet holders to position print media sheets at predetermined positionson the media support surface and restrict movement of the sheets in atleast one direction on the media support surface.
 16. The moveable trayof claim 12, further comprising moving the movable tray such that atleast a portion of the moveable tray and a portion of the media sheetsremain outside a cover enclosing a loader associated with the moveabletray and accessible to the operator when the movable tray is in anotherposition in which at least part of the moveable tray is accessible tothe loader.